- Treated brain metastases are defined as having no ongoing requirement for steroids and no evidence of progression or hemorrhage after treatment for at least 3 months, as ascertained by clinical examination and brain imaging (magnetic resonance imaging [MRI] or computed tomography [CT]); stable dose of anticonvulsants are allowed; treatment for brain metastases may include whole-brain radiotherapy (WBRT), radiosurgery (RS; Gamma Knife, linear accelerator [LINAC], or equivalent), or a combination as deemed appropriate by the treating physician